FIG. 11 is a conceptual cross sectional view illustrating an example of a conventional semiconductor device. As shown in FIG. 11, a semiconductor chip 32 is flip chip bonded on a substrate 31 which has conductor patterns formed thereon not shown in the drawing. The semiconductor chip 32 is electrically coupled with the conductor patterns on the substrate 31 not shown in the drawing via eutectic solder portions 33. In the proximity of the semiconductor chip 32, chip components 34 such as chip capacitors, and the like are attached to the substrate 31 via the eutectic solder portions 35. The chip components 34 are electrically coupled with the conductor patterns on the substrate not shown in the drawing via the eutectic solder portions 35. Underfill resin 36 is injected between a first surface of the semiconductor chip 32, that is, a surface on which circuit elements are formed and which is a surface on the bottom side of the drawing sheet, and the substrate 31. The underfill resin 36 fills a space between the first surface of the semiconductor chip 32 and the substrate 31 except the eutectic solder portions 33 and is cured to strongly fix the semiconductor chip 32 to the substrate 31.
Usually, on the first surface of the semiconductor chip 32, there are provided high temperature solder bumps not shown in the drawing, and eutectic solder portions which have lower melting point than that of the high temperature solder bumps are disposed on the substrate 31 at locations corresponding to those of the solder bumps of the semiconductor chips 32. The high temperature solder bumps of the semiconductor chip 32 and the eutectic solder portions of the substrate 31 are aligned, and heated at a temperature in which the eutectic solder melts but the high temperature solder does not melt. Thereby, only the eutectic solder portions melt, and, thereafter, the eutectic solder portions are cured. By this process, the eutectic solder potions cure such that the eutectic solder portions swallow up the solder bumps. Also, on the surface of the substrate 31 opposite to the surface on which the semiconductor chip 32 and the chip components 34 are mounted, a plurality of solder balls 37 made of the eutectic solder are disposed. The semiconductor device 50 of FIG. 11 thereby constitutes a BGA (Ball Grid Array) package structure.
When the completed semiconductor device 50 is mounted on another substrate and the like, the solder balls 37 are once melted by heating and thereafter cured, thereby the semiconductor device 50 and another substrate and the like are electrically and mechanically coupled. However, when the solder balls 37 are melted by heating, the eutectic solder portions 33 coupling the semiconductor chip 32 and the substrate 31 are also melted once similarly to the solder balls 37, by the heat conducted via the substrate 31. Therefore, there is a possibility that mutual positional relation between the substrate 31 and the semiconductor chip 32 deviates from correct positional relation and that electrical and mechanical coupling between the substrate 31 and the semiconductor chip 32 becomes unstable. Thus, when the substrate 31 and the semiconductor chip 32 are coupled only by the eutectic solder 33, electrical and mechanical coupling become unreliable. In order to avoid such disadvantage, as shown in FIG. 11, the underfill resin 36 was injected and cured between the substrate 31 and the semiconductor chip 32, thereby securing the substrate 31 and the semiconductor chip 32 by the underfill resin 36. In this structure, the heating temperature for melting the solder ball 37 made of eutectic solder is determined to be a low temperature such that the eutectic solder melts but the underfill resin 36 does not deteriorate. Thereby, high reliability of electrical and mechanical coupling between the substrate 31 and the semiconductor chip 32 can be realized.
On a second surface of the semiconductor chip 32, that is a surface on the upper side of FIG. 11, an adhesive resin 38 which is electrically conductive is applied. By the adhesive resin 38, a lid member 39 is attached to the second surface of the semiconductor chip 32, wherein the lid member 39 is made of a metal and has good heat conductivity. The lid member 39 dissipates heat produced by the semiconductor chip 32 and functions to couple the semiconductor chip 32 to the ground potential, that is, functions to ground the semiconductor chip 32. Also, there is provided an electrically conductive auxiliary board 40 which surrounds a space containing the semiconductor chip 32 and the chip components 34. The auxiliary board 40 is also bonded to the substrate 31 and to the lid member 39 by using electrically conductive adhesive resin 41. Therefore, a space 42 including the semiconductor chip 32 and the chip components 34 is electromagnetically shielded by the lid member 39 and the auxiliary board 40.
In the fabrication of the above-mentioned conventional semiconductor device 50, when the lid member 39 is bonded to the second surface of the semiconductor chip 32 and the auxiliary board 40 by the conductive adhesive resin 38, if the quantity of the conductive adhesive resin 38 applied to the second surface of the semiconductor chip 32 is too large, there is a possibility that the conductive adhesive resin 38 also reach and contact the chip components 34. FIG. 12 is a cross sectional view illustrating a situation caused when the quantity of the conductive adhesive resin 38 is too large. In such situation, there is a possibility that electrical short occurs between terminals of one chip component, between terminals of a plurality of chip components, between a chip component 34 and the semiconductor chip 32, and so on, via the conductive adhesive resin 38. Therefore, it becomes impossible for the semiconductor device 50 to perform its inherent function. On the other hand, if the quantity of the adhesive resin 38 is too small, the lid member 39 and the semiconductor 32 are not secured strongly and stably. Therefore, in the manufacturing process of the conventional semiconductor device, it is necessary to apply the conductive adhesive resin 38 on the semiconductor chip 32, very carefully.
In the above-mentioned conventional semiconductor device 50, the chip components 34 are fixed on the substrate 31 only by the eutectic solder portions 35. Therefore, securing force between each of the chip components 34 and the substrate 31 is not sufficiently large and there is a possibility that the chip components 34 come away from the substrate 31. Especially, when the semiconductor device 50 is fixed to another substrate or another component by using the solder balls 37 disposed on the surface of the substrate 31 opposite to the surface on which the semiconductor chip 32 and the chip components 34 are coupled, there occurs a problem. That is, when the solder balls 37 are heated by solder reflow process to melt the solder balls 37, the eutectic solder portions 35 coupling the chip components 34 to the substrate 31 also melt, and the chip components 34 are apt to come away from the substrate 31. Therefore, in the conventional semiconductor device 50, the eutectic solder portions 35 for fixing the chip components 34 to the substrate 31 and the solder balls 37, which are also made of eutectic solder, melt almost simultaneously and, thus, there is a high possibility that the chip components 34 are not secured strongly to the substrate 31 when the solder balls 37 melt.